;(function() {
var JPlaceHolder = {
        //检测
        _check: function() {
            return 'placeholder' in document.createElement('input');
        },
        //初始化
        init: function() {
            if (!this._check()) {
                this.fix();
            }
        },
        //修复
        fix: function() {
            jQuery(':input[placeholder]').each(function(index, element) {
                var self = $(this),
                    txt = self.attr('placeholder');
                self.wrap($('<div></div>').css({ position: 'relative', zoom: '1', border: 'none', background: 'none', padding: 'none', margin: 'none'}).addClass('placeholder'));
                var pos = self.position(),
                    h = self.outerHeight(true),
                    paddingleft = self.css('padding-left');
                var holder = $('<span></span>').text(txt).css({ position: 'absolute', left: pos.left+'px', top: pos.top+'px', height: h+'px', lineHeight: h+'px', paddingLeft: paddingleft+'px', color: '#aaa' }).appendTo(self.parent());
                if(self.val()){
                    holder.hide();
                }
                self.focusin(function(e) {
                    holder.hide();
                }).focusout(function(e) {
                    if (!self.val()) {
                        holder.show();
                    }
                });
                holder.click(function(e) {
                    holder.hide();
                    self.focus();
                });
            });
        }
    };
    //执行
    jQuery(function() {
        JPlaceHolder.init();
    });
})()